More than 400 nurses who went on a two-day strike amid disputes over pay and the availability of protective gear at a Norwich hospital have a tentative contract. The nurses and officials at the William W. Backus Hospital found common ground Saturday morning following an intervention by Gov. Ned Lamont. Nurses went on strike Tuesday and Wednesday to pressure the hospital to negotiate better contract terms and then returned to work as negotiations continued. Union officials say negotiated pay raises will help stop an exodus of nurses headed to jobs with higher salaries. They also said the hospital’s parent company agreed to single-use face masks.